Network traffic measurement typically involves multiple stages of data sampling and aggregation. Examples of such data sampling and aggregation stages include sampling of network data packets and then aggregating the sampled packets into flow statistics at, for example, a router or other network device. Subsequent stages may involve sampling and aggregation of flow statistics into usage records in a network data repository for reporting, query and archiving. Although unbiased estimates of packet, byte and/or flow statistics can be formed for each sampling and aggregation operation, for many applications knowledge of an overall estimation error is desired. Previous network traffic estimation techniques have been limited mainly to analyzing estimator variance for particular sampling and aggregation methods. However, the use of variance as a measure of estimator error assumes that estimator can be approximated by a Gaussian, or normal, distribution.